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mirror of https://github.com/systemd/systemd-stable.git synced 2024-12-24 21:34:08 +03:00
systemd-stable/libsysfs/dlist.c
2005-04-26 21:05:23 -07:00

345 lines
7.8 KiB
C

/*
* dlist.c
*
* Copyright (C) 2003 Eric J Bohm
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 021110307 USA
*
*/
/* Double linked list implementation.
* You allocate the data and give dlist the pointer.
* If your data is complex set the dlist->del_func to a an appropriate
* delete function. Otherwise dlist will just use free.
*/
#include <stdlib.h>
#include "dlist.h"
/*
* Return pointer to node at marker.
* else null if no nodes.
*/
inline void *dlist_mark(Dlist *list)
{
if(list->marker!=NULL)
return(list->marker->data);
else
return(NULL);
}
/*
* Set marker to start.
*/
inline void dlist_start(Dlist *list)
{
list->marker=list->head;
}
/*
* Set marker to end.
*/
inline void dlist_end(Dlist *list)
{
list->marker=list->head;
}
/* internal use function
* quickie inline to consolidate the marker movement logic
* in one place
*
* when direction true it moves marker after
* when direction false it moves marker before.
* return pointer to data at new marker
* if nowhere to move the marker in desired direction return null
*/
inline void *_dlist_mark_move(Dlist *list,int direction)
{
if(direction)
{
if( list->marker->next!=NULL)
list->marker=list->marker->next;
else
return(NULL);
}
else
{
if( list->marker->prev!=NULL)
list->marker=list->marker->prev;
else
return(NULL);
}
if(list->marker!=list->head)
return(list->marker->data);
else
return(NULL);
}
/*
* Create new linked list to store nodes of datasize.
* return null if list cannot be created.
*/
Dlist *dlist_new(size_t datasize)
{
Dlist *list=NULL;
if((list=malloc(sizeof(Dlist))))
{
list->marker=NULL;
list->count=0L;
list->data_size=datasize;
list->del_func=free;
list->head=&(list->headnode);
list->head->prev=NULL;
list->head->next=NULL;
list->head->data=NULL;
}
return(list);
}
/*
* Create new linked list to store nodes of datasize set list
* data node delete function to the passed in del_func
* return null if list cannot be created.
*/
Dlist *dlist_new_with_delete(size_t datasize,void (*del_func)(void*))
{
Dlist *list=NULL;
list=dlist_new(datasize);
if(list!=NULL)
list->del_func=del_func;
return(list);
}
/*
* remove marker node from list
* call data_delete function on data if registered.
* otherwise call free.
* when direction true it moves marker after
* when direction false it moves marker before.
* free marker node
* return nothing.
*/
void dlist_delete(Dlist *list,int direction)
{
if((list->marker != list->head)&&(list->marker!=NULL))
{
DL_node *corpse;
corpse=list->marker;
_dlist_mark_move(list,direction);
if(list->head->next==corpse)
list->head->next=corpse->next;
if(list->head->prev==corpse)
list->head->prev=corpse->prev;
if(corpse->prev!=NULL) //should be impossible
corpse->prev->next=corpse->next;
if(corpse->next!=NULL) //should be impossible
corpse->next->prev=corpse->prev;
list->del_func(corpse->data);
list->count--;
free(corpse);
}
}
/*
* Insert node containing data at marker.
* If direction true it inserts after.
* If direction false it inserts before.
* move marker to inserted node
* return pointer to inserted node
*/
void *dlist_insert(Dlist *list,void *data,int direction)
{
DL_node *new_node=NULL;
if(list==NULL || data==NULL)
return(NULL);
if(list->marker==NULL) //in case the marker ends up unset
list->marker=list->head;
if((new_node=malloc(sizeof(DL_node))))
{
new_node->data=data;
new_node->prev=NULL;
new_node->next=NULL;
list->count++;
if(list->head->next==NULL) //no l
{
list->head->next=list->head->prev=new_node;
new_node->prev=list->head;
new_node->next=list->head;
}
else if(direction)
{
new_node->next=list->marker->next;
new_node->prev=list->marker;
list->marker->next->prev=new_node;
list->marker->next=new_node;
}
else
{
new_node->prev=list->marker->prev;
new_node->next=list->marker;
list->marker->prev->next=new_node;
list->marker->prev=new_node;
}
list->marker=new_node;
}
else
{
return(NULL);
}
return(list->marker->data);
}
/*
* Remove DL_node from list without deallocating data.
* if marker == killme .
* when direction true it moves marker after
* when direction false it moves marker before.
* to previous if there is no next.
*/
void *_dlist_remove(Dlist *list,DL_node *killme,int direction)
{
if(killme!=NULL)
{
void *killer_data=killme->data;
// take care of head and marker pointers.
if(list->marker==killme)
_dlist_mark_move(list,direction);
if(killme ==list->head->next)
list->head->next=killme->next;
if(killme==list->head->prev)
list->head->prev=killme->prev;
// remove from list
if(killme->prev !=NULL)
killme->prev->next=killme->next;
if(killme->next !=NULL)
killme->next->prev=killme->prev;
list->count--;
free(killme);
return(killer_data);
}
else
return (NULL);
}
/*
* Insert node containing data after end.
*/
void dlist_push(Dlist *list,void *data)
{
list->marker=list->head->prev;
dlist_insert(list,data,1);
}
/*
* Insert node containing data at start.
*/
void dlist_unshift(Dlist *list,void *data)
{
list->marker=list->head->next;
dlist_insert(list,data,0);
}
/*
* Remove end node from list.
* Return pointer to data in removed node.
* Null if no nodes.
*/
void *dlist_pop(Dlist *list)
{
return(_dlist_remove(list,list->head->prev,0));
}
/*
* Remove start node from list.
* Return pointer to data in removed node.
* Null if no nodes.
*/
void *dlist_shift(Dlist *list)
{
return(_dlist_remove(list,list->head->next,1));
}
/*
* destroy the list freeing all memory
*/
void dlist_destroy(Dlist *list)
{
if(list !=NULL)
{
dlist_start(list);
dlist_next(list);
while (dlist_mark(list)) {
dlist_delete(list,1);
}
free(list);
}
}
/**
* Return void pointer to list_data element matching comp function criteria
* else null
* Does not move the marker.
*/
void *dlist_find_custom(struct dlist *list, void *target, int (*comp)(void *, void *))
{
/* test the comp function on each node */
struct dl_node *nodepointer;
dlist_for_each_nomark(list,nodepointer)
if(comp(target,nodepointer->data))
return(nodepointer->data);
return(NULL);
}
/**
* Apply the node_operation function to each data node in the list
*/
void dlist_transform(struct dlist *list, void (*node_operation)(void *))
{
struct dl_node *nodepointer;
dlist_for_each_nomark(list,nodepointer)
node_operation(nodepointer->data);
}
/**
* insert new into list in sorted order
* sorter function in form int sorter(new,ith)
* must return 1 for when new should go before ith
* else 0
* return pointer to inserted node
* NOTE: assumes list is already sorted
*/
void *dlist_insert_sorted(struct dlist *list, void *new, int (*sorter)(void *, void *))
{
for(dlist_start(list),dlist_next(list); \
list->marker!=list->head && !sorter(new,list->marker->data);dlist_next(list));
return(dlist_insert_before(list,new));
}